Results 71 to 80 of about 69,000 (198)

Energetic particles accelerated via turbulent magnetic reconnection in protoplanetary discs – I. Ionisation rates

Astronomy & Astrophysics
Context. Ionisation controls the chemistry, thermal balance, and magnetic coupling in protoplanetary discs. However, standard ionisation vectors such as stellar UV, X-rays, Galactic cosmic rays might not be efficient enough, as UV/X-rays are attenuated ...
Brunn V., Pucci F., Marcowith A., Padovani M., Rab Ch., Sauty Ch.   +5 more
doaj   +1 more source

A Cosmic Ray Acceleration Mechanism Based on Background Flow Velocity Inhomogeneities Yielding Power-law Spectra

The Astrophysical Journal
In astrophysics, one significant challenge lies in understanding the acceleration of cosmic rays, which leads to the occurrence of a power law. In this article, momentum transport generated by the combined effects of pitch-angle diffusion and background ...
J.-F. Wang, G. Qin
doaj   +1 more source

Cosmic rays: extragalactic and Galactic [PDF]

Proceedings of The 34th International Cosmic Ray Conference — PoS(ICRC2015), 2016
From the analysis of the flux of high energy particles, E > 3 10 18 eV, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, ¯ q(E) ∝ E −2.7 , with the same index of 2.7 that has the distribution of Galactic cosmic rays before so called ’knee’, E 3 10 15 eV, from the Galaxy because of the ...
openaire   +1 more source

On The Origin of Very High Energy Cosmic Rays

, 2005
We discuss the most recent developments in our understanding of the acceleration and propagation of cosmic rays up to the highest energies. In particular we specialize our discussion to three issues: 1) developments in the theory of particle acceleration
Abu-Zayyad T., Baring M. G., Berezinsky V. S., Biermann P. L., Dolag K., Dolag K., Krymskii G. F., Lagage P. O., Lagage P. O., Lemoine M., McKenzie J. F., Olinto A. V., PASQUALE BLASI, Sigl G., Sigl G., Synge J. L., Völk H. J., Zatsepin G. T.   +17 more
core   +1 more source

Cosmic X-Ray Sources-Galactic and Extragalactic.

The Astronomical Journal, 1966
Instruments carried aboard an Aerobee rocket in April 1965 provided evidence for x-ray emission from the directions of the radio galaxies Cygnus A and M-87 and from the galactic supernova remnant Cassiopeia A. A survey of the Cygnus region revealed a marked decrease in the flux of x-rays from Cygnus XR-1, which was identified in June 1964 as the second
E T, Byram, T A, Chubb, H, Friedman
openaire   +3 more sources

Gamma-ray signatures of cosmic ray acceleration, propagation, and confinement in the era of CTA

, 2012
Galactic cosmic rays are commonly believed to be accelerated at supernova remnants via diffusive shock acceleration. Despite the popularity of this idea, a conclusive proof for its validity is still missing.
A. Bamba, A. Marcowith, Acharya B. S., Actis M., Aghajani T., CTA Consortium, D. Hadasch, D. F. Torres, E. Bissaldi, E. d. Cea, E. d. Ona, et al., F. Acero, F. Volpe, G. Pedaletti, M. Renaud, O. Reimer, S. Casanova, S. Gabici, Y. Gallant   +19 more
core   +3 more sources

The AMS-02 Cosmic-Ray Deuteron Flux is Consistent with a Secondary Origin

The Astrophysical Journal Letters
The recent measurements of cosmic-ray (CR) deuteron fluxes by AMS-02 show that the rigidity dependence of deuterons is similar with that of protons but flatter than ^3 He, which has been attributed to the existence of primary deuterons with abundance ...
Qiang Yuan, Yi-Zhong Fan
doaj   +1 more source

Influence of the source distribution on the age distribution of galactic cosmic rays [PDF]

The age distribution of galactic cosmic rays in the diffusion approximation is calculated. The influence of the scale height of the spatial source distribution on the mean age of particles arriving at the solar system is discussed. The broader the source
Lerche, I., Schlickeiser, R.
core   +1 more source

A Possible Common Physics Picture Reflected by the Gamma-Ray Emission of the Galactic Center

The Astrophysical Journal
Long-term observations of the Galactic center by Fermi and HESS have revealed a novel phenomenon: the high-energy gamma-ray spectrum from the gamma-ray source HESS J1745-290 exhibits a double power-law structure.
Lin Nie, Yi-Qing Guo, Si-Ming Liu
doaj   +1 more source

Ultra-High Energy Neutrino Fluxes: New Constraints and Implications

, 2003
We apply new upper limits on neutrino fluxes and the diffuse extragalactic component of the GeV gamma-ray flux to various scenarios for ultra high energy cosmic rays and neutrinos.
, , , , , , , , , , , , , , , , , , , , , , , , , Aloisio R, AMANDA collaboration, ANTARES Collaboration, Balkanov V (BAIKAL Collaboration), Baltrusaitis R M, Barbot C, Barbot C, Berezinsky V S, Berezinsky V S, Berezinsky V S, Blasi P, Chung D J, Clark T A, Cline D B, Dedenko L G, Dmitry V Semikoz, Dokshitzer Yu L, Eberle B, Ellis R K, Fodor Z, Fodor Z, Fodor Z, For a recent review, G nter Sigl, Gorham P W, Gorham P W, Greisen K, Halzen F, Hannestad S, Hou G W, Kachelriess M, Kachelriess M, Kalashev O E, Kalashev O E, Keshet U, Kieda D, Kim H B, Kravchenko I, Kravchenko I, Kuzmin V A, Kuzmin V A, Lee S, Lehtinen N G, Montaruli T (ANTARES Collaboration), Nagano M (ed), Neronov A, Niessen P (the AMANDA Collaboration), Potgieter M S (ed), Resvanis L, Ringwald A, Rubin N, Sasaki M, See, See, See, See, See, See also Ambrosio M (MACRO Collaboration), See Hayashida N, Sigl G, Singh S, Spiering C, Stecker F W, Strong A W, Yoshida S (AGASA Collaboration), Zatsepin G T, Zatsepin G T   +91 more
core   +2 more sources